The death of a Florida man from anthrax infection has brought new scrutiny to recently imposed restrictions on the sale of deadly pathogens, which were readily obtained by countries like Iraq from global biologics-supply companies until a few years ago.

The widespread sale of deadly microbes such as anthrax and plague to nations with bioweapons programs, as well as domestic saboteurs and criminals, triggered passage of stricter laws in 1996 governing the sale and transport of deadly bacteria, viruses, fungi and toxins...